Ignition spark vacuum advance system

ABSTRACT

An ignition spark vacuum advance system for use with motor vehicle internal combustion engines. An operational amplifier responsive to a vehicle speed signal and a reference signal produces a control signal during acceleration to a speed of a selected magnitude and during deceleration at a speed less than the selected magnitude. The control signal triggers a switching transistor conductive to complete an energizing circuit for the operating coil of a two-way valve which normally establishes a vacuum connection between the carburetor vacuum spark advance port and the associated spark advance vacuum unit vacuum port and, upon the energization of the operating coil, vents the spark advance vacuum unit vacuum port to atmosphere. A temperature sensitive switch is operated to the circuit closed condition with engine temperatures less and greater than a selected engine temperature range to inhibit the switching transistor.

[ 5] July 23, 1974 IGNITION SPARK VACUUM ADVANCE SYSTEM [7 5] Inventor:Walter J. Sattler, Flint, Mich.

[73] Assignee: General Motor Corporation,

Detroit, Mich.

[22] Filed: Aug. 11, 1972 [21] Appl. No.: 279,844

[52] US. Cl. 123/117 R, 123/117 A [51] Int. Cl. F02p 5/04 [58] Field ofSearch 123/117 R, 117 A, 97 B [56] References Cited UNITED STATESPATENTS 3,476,094 11/1969 Rucins et al. 123/117 A 3,548,792 12/1970Palmer 123/97 B 3,603,298 9/1971 Toda 123/97 B 3,665,904 5/1972Goodwillie.... 123/117 A 3,680,318 8/1972 Nakajima 123/117 A 3,687,1208/1972 Lenz 123/117 A 3,721,221 3/1973 Okada 123/117 A PrimaryExaminerLaurence M. Goodridge Assistant Examiner-Cort Flint Attorney,Agent, or FirmRichard G. Stahr [57] ABSTRACT An ignition spark vacuumadvance system for use with motor vehicle internal combustion engines.An operational amplifier responsive to a vehicle speed signal and areference signal produces a control signal during acceleration to aspeed of a selected magnitude and during deceleration at a speed lessthan the selected magnitude. The control signal triggers a switchingtransistor conductive to complete an energizing circuit for theoperating coil of a two-way valve which normally establishes a vacuumconnection between the carburetor vacuum spark advance port and theassociated spark advance vacuum unit vacuum port and, upon theenergization of the operating coil, vents the spark advance vacuum unitvacuum port to atmosphere. A temperature sensitive switch is operated tothe circuit closed condition with engine temperatures less and greaterthan a selected engine temperature range to inhibit the switchingtransistor.

6 Claims, 1 Drawing Figure 'IIIIIIIIIIIII l IGNITION SPARK VACUUMADVANCE SYSTEM This invention is directed to an ignition spark vacuumadvance system and, more specifically, to an ignition spark vacuumadvance system for use with motor vehicle internal combustion engineswhich provides ignition spark retard at vehicle or engine speeds lessthan a preselected magnitude with normal engine temperatures and normalignition spark vacuum advance at any vehicle or engine speed with a coldor overheated engme.

In an effort to reduce the undesirable emissions of the exhaust ofinternal combustion engines employed to drive motor vehicles, variousignition spark control systems have been developed which preventignition spark vacuum advance during low vehicle speeds. One undesirableconsequence of systems of this type is the difficulty of a cold engineto start properly in cold weather and drive the vehicle withoutstalling. Furthermore, since internal combustion engines heat morerapidly with a retarded spark, there is a tendency for the engine tooverheat at low vehicle speeds, such as encountered in slow traffic orstanding, with the spark retarded.

It is therefore, an object of this invention to provide an improvedignition spark vacuum advance system for use with motor vehicle internalcombustion engines.

It is another object of this invention to provide an improved ignitionspark vacuum advance system for use with motor vehicle internalcombustion engines which, at low vehicle or engine speeds, disenablesthe ignition spark vacuum advance mechanism while the engine is atnormal operating temperature and enables the ignition spark vacuumadvance mechanism at any vehicle or engine speed while the engine isoperating at temperatures less than and greater than a selected enginetemperature range.

In accordance with this invention, a motor vehicle internal combustionengine ignition spark vacuum advance system which retards the ignitionspark at low vehicle or engine speeds with engine temperatures within aselected range and provides normal ignition spark vacuum advance at anyvehicle or engine speed with engine temperatures not within the selectedrange is provided wherein a switching transistor having thecollector-emitter electrodes connected in series in the energizationcircuit of the operating coil of a two-way valve, the energization ofwhich operates the valve to a condition which vents the vacuum port ofan associated spark advance mechanism vacuum unit to atmosphere, istriggered conductive through the collectoremitter electrodes in responseto a control signal produced during vehicle acceleration until thevehicle has accelerated to a speed of a selected magnitude and duringvehicle deceleration after the vehicle has decelerated to a speed lessthan the selected magnitude and a temperature sensitive switch isoperated to the electrical circuit closed condition in response toengine temperatures less than and greater than a selected enginetemperature range to inhibit the switching transistor.

For a better understanding of the present invention, together withadditional objects, advantages and features thereof, reference is madeto the following description and accompanying single FIGURE drawingwhich sets forth the ignition spark vacuum advance system of thisinvention in schematic form.

The ignition spark vacuum advance system for use with motor vehicleinternal combustion engines of this invention operates incombinationwith a conventional automotive type carburetor 10 having a vacuum sparkadvance port 12; an ignition distributor 14, shown in top plan view inthe FIGURE, having an ignition spark advance mechanism operated by aspark advance vacuum unit 18 having a vacuum port 19 and a source ofdirect current potential, which may be a conventional automotive typebattery 8.

Carburetor 10 may be of conventional design having a vacuum sparkadvance port 12 which opens into the carburetor mixing conduit 16,through which the airfuel mixture is conducted to the intake manifold15, just above the throttle plate 17. At idle or conditions of very lowspeed, throttle plate 17 is closed or nearly closed, consequently,carburetor vacuum spark advance port 12 is exposed to substantiallyatmospheric pressure, as shown in the FIGURE. As the throttle plate 17is revolved to open in a counterclockwise direction, as viewing theFIGURE, carburetor vacuum spark advance port 12 becomes exposed to theengine intake manifold vacuum.

Ignition distributor 14 may be of conventional design having an ignitionspark advance mechanism of conventionaldesign operated by a sparkadvance vacuum unit 18 having a vacuum port 19. As ignition spark vacuumadvance mechanisms of this type are well known in the automotive artand, per se, form no part of this invention, it has not been illustratedin detail in the FIGURE. The operation will be explained in greaterdetail later in this specification.

Extending between the carburetor vacuum spark advance port 12 and thespark advance vacuum unit vacuum port 19 is a vacuum line which includesvacuum line segments 20 and 21 and a two-way valve 22, having anoperating member or rod 23, which is operated to a first position bycompression spring 24 to establish a vacuum connection between thecarburetor vacuum spark advance port 12 and spark advance vacuum unitvacuum port 19 and is operable to a second position upon theenergization of operating coil 25 to vent the spark advance vacuum unitvacuum port 19 to atmosphere. Two-way valve 22 is illustrated in theFIGURE as having a center chamber 26 and two outside chambers 27 and 28separated by respective walls 29 and 30. Each of chambers 26, 27 and 28communicates externally of valve 22 through respective ports 31, 32 and33. Internally of valve 22, center chamber 26 communicates with outsidechamber 28 through an inside port 34 having an angularly disposed valveseat 35 and with the other outside chamber 27 through an inside port 36having an angularly disposed valve seat 37. Port 31 of two-way valve 22is interconnected with the spark advance vacuum unit vacuum port 19through vacuum line segment 21, port 32 is interconnected with thecarburetor vacuum spark advance port 12 through vacuum line segment 20and port 33 is vented to atmosphere. Secured to the end of operatingmember 23 within valve 22 is a piston 38 having two angularly disposedfaces 39 and 40 which are arranged to engage respective angularlydisposed valve seats 35 and 37 in a tight complementary fit. Valve 22 isoperated to the first condition by compression spring 24 and is operatedto the second condition by energizing operating coil 25 which moves rod23 linearly in an upward direction as viewing the FIGURE. In the firstcondition of 3 valve 22, face 39 of piston 38 is in tight complementaryfit with valve seat 35 to provide an open passage therethrough betweenonly ports 31 and 32 and in the second condition, face 40 of piston 38is in a tight complementary fit with valve seat 37 to provide an openpassage therethrough between only ports 31 and 33. It is to bespecifically understood that two-way valve 22 of the FIGURE is only oneexample of many two-way valves which may be employed for thisapplication.

With conventional ignition spark vacuum advance mechanism, thecarburetor vacuum spark advance port is directly interconnected througha vacuum line with the spark advance vacuum unit vacuum port. The sparkadvance vacuum unit 18 may be any one of the many vacuum units wellknown in the automotive art.

Mounted within the distributor 14 is a movable breaker plate, upon whichthe ignition breaker contact points are mounted, which is rotatable in aplane nor- I mal to the axis of the distributor drive shaft to advanceand retard the engine ignition spark. This movable breaker plate isrevolved by an operating arm, such as that referenced by the numeral 41in the FIGURE, which is attached to and moved by a diaphragm within thespark advance vacuum unit 18 through a push rod 42 in a manner wellknown in the automotive art.

As vehicle acceleration, deceleration and rate of speed is directlyproportional to engine speed, the ignition spark vacuum advance systemof this invention will be herein described in relation to engine speed.

At idle or conditions of low engine speed, with the carburetor throttleplate closed or nearly closed, the carburetor vacuum spark advance port12 is exposed to atmospheric pressure, consequently, the diaphragmwithin the spark advance vacuum unit 18 is exposed to atmosphere on bothsides. Under these conditions, the diaphragm and connected operating rod42 are forced by a spring, also within the spark advance vacuum unit 18,in a direction which will rotate the movable breaker plate withindistributor 14 in the direction which will retard the ignition spark.With the carburetor throttle plate 17 open during acceleration orcruising speed, the carburetor vacuum spark advance port 12 is exposedto engine intake manifold vacuum, the diaphragm with the spark advancevacuum unit 18 is exposed to manifold vacuum on the side of the vacuumport 19. Under these conditions, the diaphragm within the spark advancevacuum unit 18 and connected operating rod 42 are forced in the oppositedirection by the greater pressure on the side of the diaphragm vented toatmosphere to rotate the movable breaker plate in the direction whichwill advance the ignition spark. From this description, it is apparentthat with two-way valve 22 in the first condition of operation with face39 of piston 38 in tight complementary fit with valve seat 35, theignition spark vacuum advance mechanism illustrated in the FIGURE willoperate in a normal manner.

In the FIGURE, the output potential of battery 8 is shown to beregulated by Zener diode 44. It is to be specifically understood thatthis potential regulating arrangement is not absolutely necessary forthe practice of this invention.

As point of reference or ground potential is the same point electricallythroughout the system, it has been illustrated in the FIGURE by theaccepted schematic symbol and referenced by the numeral 5.

One method, and without intention or inference of a limitation thereto,for producing a direct current speed signal of a magnitude proportionalto vehicle speed may be a type NPN transistor 50 operating as a class Aamplifier having the collector electrode 52 and emitter electrode 53thereof connected across the positive and negative polarity terminals,respectively, of battery 8 through collector resistor 54 and leads and43 and point of reference or ground potential 5, respectively; theparallel combination of capacitor 55 and resistor 56 connected acrossthe collector electrode 52 and the base electrode 51 of transistor andthe parallel combination of capacitor 57 and diode 58 in series and thecontacts 66 and 67 of a magnetically operated reed switch 65 connectedacross battery 8 through current limiting resistor 59 and leads 45 and43 andpoint of reference or ground potential 5. Member 70 may be anymember which may be conveniently rotated at a speed equal to orproportional to vehicle or engine speed which is arranged to carry aplurality of permanent magnets, four of which are illustrated in theFIG- URE and referenced by the numerals 71, 72, 73, and 74. For example,member 70 may be a drum mounted upon the engine crankshaft, it may be amember mounted upon the engine flywheel or a member mounted upon anyother vehicle part which is rotated at a speed equal to or proportionalto vehicle or engine speed. It is only necessary that the permanentmagnets rotated thereby are in operative relationship with the contacts66 and 67 of reed switch 65 to operate these contacts to the electricalcircuit open and closed conditions at a frequency proportional tovehicle or engine speed by passing in close proximity thereto in amanner well known in the art. While the contacts 66 and 67 of reedswitch 65 are open, capacitor 57 charges through resistor 59 and diode58 and while the contacts 66 and 67 of reed switch 65 are closed, adischarge circuit is established therethrough for capacitor 57.

Discharging capacitor 57 reduces the'positive polarity potential uponthe base electrode 51 of type NPN transistor 50 thereby decreasing thecollector-emitter conduction therethrough as a class A amplifier.Capacitor charges through the relatively low value resistances 54 and 78and diodes 78 and 58 and discharges through high resistance 56 or muchmore rapidly through the collector-emitter electrodes of type NPNtransistor 50, depending upon the degree of its conductivity.Consequently, the'more frequently contacts 66 and 67 of reed switch areoperated to the electrical circuit closed condition by the magnetscarried upon rotating member with increases of vehicle or engine speed,the lower the degree of conduction through type NPN transistor 50. Ascapacitor 55 discharges more slowly with a decrease of conductionthrough transistor 50, the potential appearing across junction 68 andpoint of reference or ground potential 5, the speed signal which is of apositive polarity upon junction 68 with respect to point of reference orground potential 5, increases in magnitude. Consequently, this speedsignal potential is of a magnitude proportional to vehicle speed.

To produce a direct current reference signal of a predeterminedsubstantially constant magnitude, the series combination of a resistor46 and the Zener diode 47 may be connected across battery 8 throughleads 45 and 43 and point of reference or ground potential 5. Zenerdiode 47 is selected to have an inverse breakdown potential of amagnitude equal to the selected predetermined magnitude. Consequently,the direct current reference signal potential appearing across junction48 and point of reference or ground potential 5 of a positive polarityupon junction 48 with respect to point of reference or ground potential5 remains substantially constant at a magnitude equal to the inversebreakdown potential of the Zener diode selected as Zener diode 47. Inone specific embodiment of the internal combustion engine ignition sparkadvance system of this invention, the selected Zener diode correspondingto Zener diode 47 had an inverse breakdown potential of seven volts.

Circuitry responsive to the speed signal appearing across junction 68and point of reference or ground potential 5 and the reference signalappearing across junction 48 and point of reference or ground potential5 for producing a control signal during vehicle acceleration until thevehicle has accelerated to a speed of a selected magnitude and duringvehicle deceleration after the vehicle has decelerated to a speed lessthan the selected magnitude may be a conventional operational amplifier75 having an inverting input circuit, referenced in the FIGURE as aminus sign, and a non-inverting input circuit, referenced in the FIGUREas a plus sign, and an output circuit 76, operating in the open loopmode. When operating in the open loop mode, operational amplifiersfunction as an extremely sensitive and rapidly operating electricalswitch produces an output signal of a positive polarity upon the outputterminal 76 thereof with respect to point of reference or groundpotential 5 when a positive polarity potential is applied to theinverting input circuit of a magnitude less than the positive polaritypotential applied to the non-inverting input circuit and produces anoutput signal of substantially ground potential when a positive polaritypotential is applied to the inverting input circuit of a magnitudegreater than the positive polarity potential applied to thenon-inverting input circuit. To provide the hysteresis required foroperational amplifier 75 to produce the control signal during vehicleacceleration until the vehicle has accelerated to a speed of a selectedmagnitude and during vehicle deceleration after the vehicle hasdecelerated to a speed less than the selected magnitude, a feedbackresistor 77 is connected between output circuit 76 and the noninvertinginput circuit thereof.

Circuitry responsive to the control signal produced by operationalamplifier 75 for completing an energizin g circuit for the operatingcoil 25 of two-way valve 22 across the source of direct currentpotential may be any electrical switching device having normally opencurrent carrying elements, operable to an electrical circuit closedcondition in response to an electrical signalsuch as the control signal,connected in series with the operating coil 25 of two-way valve 22across the source of direct current potential. In the FIGURE, andwithout intention or inference of a limitation thereto, this electricalswitching device is illustrated as a type NPN transistor 60 having thecollector electrode 62 and emitter electrode 63 thereof connected inseries with operating coil 25 of two-way valve 22 across battery 8through a circuit which may be traced from the positive polarityterminal of battery 8 through lead 43, lead 49, operating coil 25 oftwo-way valve 22, lead 64 and the collector-emitter electrodes oftransistor 60 to point of reference or ground potential 5. With someapplications, the base electrode 61 of transistor 60 may be connected tooutput circuit 76 of operational amplifier 75 through current limitingresistor 69. Alternatively, a type NPN driver transistor 80 having thecollector electrode 82 thereof connected to the positive polarityterminal of battery 8 through lead 84, collector resistor 85 and leads45 and lead 43 and the emitter electrode 83 thereof connected to thenegative polarity terminal of battery 8 through lead 86, thebase-emitter electrodes of transistor and point of reference or groundpotential 5 may be connected between output circuit 76 of operationamplifier 75 and switching transistor 60 and the base electrode 81thereof connected to output circuit 76 of operational amplifier 75through current limiting resistor 69. With the first alternative,switching transistor 60 is responsive to the control signal forcompleting an energizing circuit for operating coil 25 of two-way valve22 and with the second alternative, drive transistor 80 and switchingtransistor 60 are responsive to the control signal for completing anenergizing circuit for operating coil 25 of two-way valve 22.

The device responsive to engine temperatures less than and greater thana selected engine temperature range, for example, 140 to 160 F forinhibiting the circuitry responsive to the control signal, eitherswitching transistor 60 or driver transistor 80 and switching transistor60, may be a temperature sensitive switch 90 having a movable contact 91and two stationary contacts 92 and 93. This temperature sensitive switchmay be connected across the base electrode 81 of driver transistor 80and point of reference or ground potential 5, as shown in the FIGURE,or, alternatively, it may be connected across the base electrode 61 ofswitching transistor 60 or across the non-inverting input circuit ofoperational amplifier 75 and point of reference or ground potential 5.Switch 90 may be any one of the many temperature sensitive switcheshaving a movable contact which is operated to an electrical circuitclosed condition to one associated stationary contact with enginetemperatures below a selected minimum and to an electrical circuitclosed condition to the other associated stationary contact with enginetemperatures greater than a selected minimum.

Assuming that the associated internalcombustion engine, not shown, isoperating the vehicle at idle or low engine speed within the selectedengine temperature range, transistor 50 is operating as a class Aamplifier and the contacts 66 and 67 of reed switch are being slowlyoperated by the magnets upon rotating member 70 and capacitor 55 ischarged through resistor 54, resistor 78, diode 79 and diode 58. Withthese conditions, the reference potential appearing across junction 48and point of reference or ground potential 5, applied to thenon-inverting input circuit of operational amplifier through lead 87 andresistor 88 is of a magnitude greater than the speed signal appearingacross junction 68 and point of reference or ground potential 5, appliedto the inverting input circuit of operational amplifier 75 through lead94 and resistor 95. As the positive polarity potential applied to thenon-inverting inverting input circuit of operational amplifier 75 is ofa magnitude greater than the positive polarity potential applied to theinverting input circuit thereof, operational amplifier 75 produces anoutput control signal upon output circuit 76 thereof of a positivepolarity upon output circuit 76 with respect to point of reference orground potential 5. As this control signal is applied across thebase-emitter electrodes of type NPN driver transistor through resistor69 in the proper polarity relationship to produce base-emitter drivecurrent through a type NPN transistor, driver transistor 80 is triggeredconductive through the collector-emitter electrodes thereof to supplybase drive current to switching transistor 60 through leads 43 and 45,collector resistor 85, lead 84, the collector-emitter electrodes oftransistor 80, lead 86, the base-emitter electrodes of type NPNswitching 60 and point of reference or ground potential 5. This basedrive current supplied to switching transistor 60 triggers this deviceconductive through the collector-emitter electrodes thereof to completean energizing circuit for operating coil 25 of two-way valve 22 whichmay be traced from the positive polarity terminal of battery 8, throughleads 43 and 49, operating coil 25, lead 64, the collector-emitterelectrodes of switching transistor 60 and point of reference or groundpotential to the negative polarity terminal of battery 8. It may benoted that with applications in which driver transistor 80 is eliminatedand the base electrode 61 of type NPN switching transistor 60 isconnected to output circuit 76 of operational amplifier 75 throughresistor 69, the positive polarity control signal upon output circuit 76of operational amplifier 75 is of the proper polarity relationship toproduce base drive current through type NPN switching transistor 60 totrigger this device conductive through the collector-emitter electrodesto establish the same energizing circuit for operating coil 25 oftwo-way valve 22. Upon the energization of operating coil 25, two-wayvalve 22 is operated to the second condition in which the vacuum port 19of spark advance vacuum unit 18 is vented to atmosphere through port 31of valve 22, center chamber 26, internal port 34, outside chamber 28 andport 33. With vacuum port 19 of spark advance vacuum unit 18 vented toatmosphere, theignition spark vacuum advance mechanism is disabled andthe ignition spark is retarded at these low engine and, consequently,vehicle speeds. As the speed of the engine is increased to acceleratethe vehicle, the magnets carried by rotating member 70 operate contacts66 and 67 of reed switch 65 more rapidly to the electrical circuit openand closed conditions to reduce the degree of conduction throughtransistor 50 for the reason previously set forth. A decreased degree ofconduction through transistor 50 results in the retentionof a charge ofincreased magnitude upon capacitor 55 as it is not as rapidly dischargedthrough conducting transistor 50. Consequently, as the engine continuesto accelerate the vehicle, the speed signal appearing across junction 68and point of reference or ground potential 5 continues to increase inmagnitude with increases of engine and vehicle speed until the vehiclehas been accelerated to a speed of a selected magnitude, for example 30miles per hour, at which the magnitude of the speed signal appearingacross junction 68 and point of reference or ground potential 5 is of amagnitude greater than the reference potential appearing across junction48 and point of reference or ground potential 5. With these conditions,the positive polarity speed signal potential applied to the invertinginput circuit of operational amplifier 75 is of a magnitude greater thanthe reference signal potential applied to the non-inverting inputcircuit of operational amplifier 75, consequently, the control signal isremoved from output circuit 76 which is now of substantially groundpotential. With output circuit 76 of operational amplifier 75 at groundpotential, base drive current is no longer supplied to driver transistor80, consequently, this device extinguishes. With driver transistor 80extinguished, the circuit through which base drive current is suppliedto type NPN switching transistor is interrupted, consequently, switchingtransistor 60 extinguishes to interrupt the energizing circuit ofoperating coil 25 of two-way valve 22. Upon the deenergization ofoperating coil 25, compression spring 24 operates piston 38 of two-wayvalve 22 into a tight complementary fit with valve seat 35 to placevalve 42 in the first condition. With two-way valve 22 in the firstcondition, a vacuum connection is established between the carburetorspark advance port 12 and the spark advance vacuumunit l8 vacuum port 19through vacuum line segment 20, port 32 of valve 22, outside chamber 27,internal port 36, center chamber 26, port 31 and vacuum line segment 21.With the establishment of this vacuum connection, the internalcombustion engine ignition spark vacuum advance mechanism operates in anormal manner to provide ignition spark advance in accordance withengine vacuum. .It may be noted that with applications in which drivertransistor 80 is eliminated and the base electrode 61 of typeNPNswitching transistor 60 is connected to output circuit 76 of operationalamplifier 75 through resistor 69, a ground potential signal upon outputcircuit 76 of operational amplifier 75 will remove base drive currentfrom switching transistor 60 to extinguish this device and interrupt theenergizing circuit for operating coil 25 of two-way valve22.

During deceleration, the contacts 66 and 67 of reed switch are operatedat a proportionately lower rate, consequently, the degree of conductionthrough transistor 50 begins to increase proportionately, resulting in aproportionate decrease of the magnitude of the speed signal appearingacross junction 68 and point of reference or ground potential 5.However, the ground potential upon output circuit 76 of operationalamplifier 75, applied to the non-inverting input circuit thereof throughfeedback resistor 77, effectively reduces the magnitude of the positivepolarity reference potential also applied to the non-inverting inputcircuit. Consequently, the positive polarity speed signal applied to theinverting input circuit of operational amplifier is of a relativelygreater magnitude. Therefore, upon deceleration, the magnitude of thepositive polarity reference signal potential applied to thenon-inverting input circuit of operational amplifier 75 will not exceedthe realtive magnitude of the positive polarity speed signal potentialapplied to the inverting input circuit thereof until the speed signalpotential has reduced to a value lower than that corresponding to thespeed of the selected magnitude, for example at 20 miles per hour. Withthis arrangement, a hysteresis is introduced into the system to provideincreased stability and smoothness of vehicle operation. As the engineand vehicle continue to decelerate until a speed is reached at which thereference signal potential is of a magnitude greater than the relativespeed signal potential operational amplifier 75 again produces the.control signal upon the output circuit 76 thereof. Upon the appearanceof this control signal, driver transistor 80 and switching transistor 60or, alternatively, only switching transistor 60 in the event drivertransistor 80 is not employed, again establishes the energizing circuitfor operating coil 25 of two-way valve 22 to operate two-way valve 22 tothe second condition which vents the vacuum port 19 of spark advancevacuum unit 18 to atmosphere. With vacuum port 19 vented to atmosphere,the ignition spark is retarded at these low engine speeds.

Should the vehicle or engine be operating at any speed at a temperatureless than the selected engine temperature range, movable contact 91 oftemperature sensitive switch 90 is operated to the circuit closedcondition to one of stationary contacts 92 or 93 and should the vehicleor engine be operating at any speed at a temperature greater than theselected engine temperature range, movable contact 96 of temperaturesensitive switch 95 is operated to the electrical circuit closedcondition to the other one of stationary contacts 97 or 98. Upon theclosure of movable contact 91 of temperature sensitive switch 90 toeither one of stationary contacts 92 or 93, base drive current isdiverted from driver transistor 80 with the circuit connections in theFIGURE. With base drive current diverted fromdriver transistor 80, thisdevice does not conduct to supply base drive current to switchingtransistor 60, consequently, an energizing circuit is not establishedfor operating coil of two-way valve 22. Should temperature sensitiveswitch 90 be connected across the base electrode 61 of switchingtransistor 60 and point of reference or ground potential 5, base drivecurrent sup plied by driver transistor 80 would be diverted fromswitching transistor 60, a condition which prevents switching transistor60 from conducting through the collector-emitter electrodes to establishthe energizing circuit for operating coil 25 of two-way valve 22. Shouldtemperature sensitive switch 90 be connected across the non-invertinginput circuit of operational amplifier 75 and point of reference orground potential 5, any speed signal potential magnitude would result ina ground potential signal upon output circuit 76 thereof, a conditionwhich would trigger neither driver transistor 80 nor switchingtransistor 60 conductive through the collector-emitter electrodes,consequently, the energizing circuit for operating coil 25 of two-wayvalve 22 would not be established. Consequently, at any engine speedwhile the engine is operating at a temperature greater than or less thanthe selected engine temperature range, temperature sensitive switch 90inhibits the circuitry through which the energizing circuit isestablished for operating coil 25 of twoway valve 22 and the ignitionvacuum spark advance mechanism of the associated engine operates in anormal manner to advance the ignition spark in accordance with enginevacuum.

While a preferred embodiment of the present invention has been shown anddescribed, it will be obvious to those skilled in the art that variousmodifications and substitutions may be made without departing from thespirit of the invention which is to be limited only within the scope ofthe appended claims.

What is claimed is:

1. An ignition spark vacuum advance system for use with motor vehicleinternal combustion engines comprising in combination with a carburetorhaving a spark advance port, an ignition distributor having an ignitionspark advance mechanism operated by a spark advance vacuum unit having avacuum port and a source of direct current potential, a vacuum lineextending between said carburetor spark advance port and said sparkadvance vacuum unit vacuum port, a two-way valve having an operatingcoil included in said vacuum line which is normally in a first conditionto establish a vacuum connection between said carburetor spark advanceport and said spark advance vacuum unit vacuum port and operable, uponthe energization of said operating coil, to a second condition to ventsaid vacuum advance unit vacuum port to atmosphere, means for producinga direct current speed signal of a magnitude proportional to vehicle'speed, means for producing a direct current reference signal of apredetermined substantially constant magnitude, means responsive to saidspeed signal and said reference signal for producing a control signalduring vehicle acceleration until said vehicle has accelerated to aspeed of a selected magnitude and during deceleration after said vehiclehas decelerated to a speed less than the selected magnitude, and meansresponsive to said control signal for completing an energizing circuitfor said operating coil of said two-way valve across said source ofdirect current potential.

2. An ignition spark vacuum advance system for use with motor vehicleinternal combustion engines comprising in combination with a carburetorhaving a spark advance port, anignition distributor having an ignitionspark advance mechanism operated by a spark advance vacuum unit having avacuum port and a source of direct current potential, a vacuum lineextending between said carburetor spark advance port and said sparkadvance vacuum unit vacuum port, a two-way valve having an operatingcoil included in said vacuum line which is normally in a first conditionto establish a vacuum connection between said carburetor spark advanceport and said spark advance vacuum unit vacuum port and operable, uponthe energization of said operating coil, to a second condition to ventsaid vacuum advance unit vacuum port to atmosphere, means for producinga direct current speed signal of a magnitude proportional to vehiclespeed, means for producing a direct current reference signal of apredetermined substantially constant magnitude, means responsive to saidspeed signal and said reference signal for producing a control signalduring vehicle acceleration until said vehicle has accelerated to aspeed of a selected magnitude and during deceleration after said vehiclehas decelerated to a speed less than the selected magnitude, meansresponsive to said control signal for completing an energizing circuitfor said operating coil of said two-way valve across said source ofdirect current potential, and means responsive to engine tempera turesless than and greater than a selected engine temperature range forinhibiting said means responsive to said control signal.

3. An ignition spark vacuum advance system for use with motor vehicleinternal combustion engines comprising in combination with a carburetorhaving a spark advance port, an ignition distributor having an ignitionspark advance mechanism operated by a spark advance vacuum unit having avacuum port and a source of direct current potential, a vacuum lineextending between said carburetor spark advance port and said sparkadvance vacuum unit vacuum port, a two-way valve having an operatingcoil included in said vacuum line which is normally in a first conditionto establish a vacuum connection between said carburetor spark advanceport and said spark advance vacuum unit vacuum port and operable, uponthe energization of said operating coil, to a second condition to ventsaid vacuum advance unit vacuum port to atmosphere, means for producinga direct current speed signal of a magnitude proportional to vehiclespeed, means for producing a direct current reference signal of apredetermined substantially constant magnitude, means responsive to saidspeed signal and said reference signal for producing a control signalduring vehicle acceleration until said vehicle has accelerated to aspeed of a selected magnitude and during deceleration after said vehiclehas decelerated to a speed less than the selected magnitude, anelectrical switching device having normally open current carryingelements operable to an electrical circuit closed condition in responseto said control signal, and means for connecting said current carryingelements of said electrical switching device and said operating coil ofsaid two-way valve in series across said source of direct currentpotential.

4. An ignition spark vacuum advance system for use with motor vehicleinternal combustion engines comprising in combination with a carburetorhaving a spark advance port, an ignition distributor having an ignitionspark advance mechanism operated by a spark advance vacuum unit having avacuum port and a source of direct current potential, a vacuum lineextending between said carburetor spark advance port and said sparkadvance vacuum unit vacuum port, a two-way valve having an operatingcoil included in said vacuum line which is normally in a first conditionto establish a vacuum connection between said carburetor spark advanceport and said spark advance vacuum unit vacuum port and operable, uponthe energization of said operating coil, to a second condition to ventsaid vacuum advance unit vacuum port to atmosphere, means for producinga direct current speed signal of a magnitude proportional to vehiclespeed, means for producing a direct current reference signal of apredetermined substantially constant magnitude, means responsive to saidspeed signal and said reference signal for producing a control signalduring vehicle acceleration until said vehicle has accelerated to aspeed of a selected magnitude and during deceleration after said vehiclehas decelerated to a speed less than the selected magnitude, anelectrical switching device having normally open current carryingelements operable to an electrical circuit closed condition in responseto said control signal, means for connecting said current carryingelements of said electrical switching device and said operating coil ofsaid two-way valve in series across said source of direct currentpotential, and means responsive to engine temperatures less than andgreater than a selected engine temperature range for diverting saidcontrol signal from said electrical switching device.

5. An ignition spark vacuum advance system for use with motor vehicleinternal combustion engines comprising in combination with a carburetorhaving a spark advance port, an ignition distributor having an ignitionspark advance mechanism operated by a spark advance vacuum unit having avacuum port and a source of direct current potential, a vacuum lineextending between said carburetor spark advance port and said sparkadvance vacuum unit vacuum port, a two-way valve having an operatingcoil included in said vacuum line which is normally in a first conditionto establish a vacuum connection between said carburetor spark advanceport and said spark advance vacuum unit vacuum port and operable, uponthe energization of said operating coil, to a second condition to ventsaid vacuum advance unit vacuum port to atmosphere, means for producinga direct current speed signal of a magnitude proportional to vehiclespeed, means for producing a direct current reference signal of apredetermined substantially constant magnitude, an operational amplifierhaving an inverting input circuit, a non-inverting input circuit and anoutput circuit for producing a control signal upon said output circuitthereof during vehicle acceleration until said vehicle has acceleratedto a speed of a selected magnitude and during deceleration after saidvehicle has decelerated to a speed less than the selected magnitude,means for applying said direct current speed signal to said invertinginput circuit of said operational amplifier, means for applying saiddirect current reference signal to said non-inverting input circuit ofsaid operational amplifier, and means responsive to said control signalfor completing an energizing circuit for said operating coil of saidtwo-way valve across said source of direct current potential.

6. An ignition spark vacuum advance system for use with motor vehicleinternal combustion engines comprising in combination with a carburetorhaving a spark advance port, an ignition distributor having an ignitionspark advance mechanism operated by a spark advance vacuum unit having avacuum port and a source of direct current potential, a vacuum lineextending between said carburetor spark advance port and said sparkadvance vacuum unit vacuum port, a two-way valve having an operatingco'il included in said vacuum line which is normally in a firstcondition to establish a vacuum connection between said carburetor sparkadvance port and said spark advance vacuum unit vacuum port andoperable, upon the energization of said operating coil, to a secondcondition to vent said vacuum advance unit vacuum port to atmoosphere,means for producing a direct current speed signal of a magnitudeproportional to vehicle speed, means for producing a direct currentreference signal of a predetermined substantially constant magnitude, anoperational amplifier having an inverting input circuit, a non-invertinginput circuit and an output circuit for producing a control signal uponsaid output circuit thereof during vehicle acceleration until saidvehicle has accelerated to a speed of a selected magnitude and duringdeceleration after said vehicle has decelerated to a speed less than theselected magnitude, means for applying said direct current speed signalto said inverting input circuit of said operational amplifier, means forapplying said direct current reference signal to said non-invertinginput circuit of said operational amplifier, means responsive to saidcontrol signal for completing an energizing circuit for said operatingcoil of said two-way valve across said source of direct currentpotential, and means responsive to engine temperatures less than andgreater than a selected engine temperature range for inhibiting saidmeans responsive to said control signal.

I PC1-1050 1 UNITED STATES PATENT OFFICE 5 9 CERTIFICATE OF CORRECTIONPatent No. 3,824,972 Dated July 23, 1974 Inventor-(S) Walter J. Settle:

It is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below: I

F Column 6, line 41, delete "minimum" and insert maximum Signed andsealed this 15th day of October 1974.

(SEAL) Attest:

McCOY M. GIBSON JR. C. MARSHALL DANN Attesting Officer Commissioner ofPatents

1. An ignition spark vacuum advance system for use with motor vehicleinternal combustion engines comprising in combination with a carburetorhaving a spark advance port, an ignition distributor having an ignitionspark advance mechanism operated by a spark advance vacuum unit having avacuum port and a source of direct current potential, a vacuum lineextending between said carburetor spark advance port and said sparkadvance vacuum unit vacuum port, a two-way valve having an operatingcoil included in said vacuum line which is normally in a first conditionto establish a vacuum connection between said carburetor spark advanceport and said spark advance vacuum unit vacuum port and operable, uponthe energization of said operating coil, to a second condition to ventsaid vacuum advance unit vacuum port to atmosphere, means for producinga direct current speed signal of a magnitude proportional to vehiclespeed, means for producing a direct current reference signal of apredetermined substantially constant magnitude, means responsive to saidspeed signal and said reference signal for producing a control signalduring vehicle acceleration until said vehicle has accelerated to aspeed of a selected magnitude and during deceleration after said vehiclehas decelerated to a speed less than the selected magnitude, and meansresponsive to said control signal for completing an energizing circuitfor said operating coil of said two-way valve across said source ofdirect current potential.
 2. An ignition spark vacuum advance system foruse with motor vehicle internal combustion engines comprising incombination with a carburetor having a spark advance port, an ignitiondistributor having an ignition spark advance mechanism operated by aspark advance vacuum unit having a vacuum port and a source of directcurrent potential, a vacuum line extending between said carburetor sparkadvance port and said spark advance vacuum unit vacuum port, a two-wayvalve having an operating coil included in said vacuum line which isnormally in a first condition to establish a vacuum connection betweensaid carburetor spark advance port and said spark advance vacuum unitvacuum port and operable, upon the energization of said operating coil,to a second condition to vent said vacuum advance unit vacuum port toatmosphere, means for producing a direct current speed signal of amagnitude proportional to vehicle speed, means for producing a directcurrent reference signal of a predetermined substantially constantmagnitude, means responsive to said speed signal and said referencesignal for producing a control signal during vehicle acceleration untilsaid vehicle has accelerated to a speed of a selected magnitude andduring deceleration after said vehicle has decelerated to a speed lessthan the selected magnitude, means responsive to said control signal forcompleting an energizing circuit for said operating coil of said two-wayvalve across said source of direct current potential, and meansresponsive to engine temperatures less than and greater than a selectedengine temperature range for inhibiting said means responsive to saidcontrol signal.
 3. An ignition spark vacuum advance system for use withmotor vehicle internal combustion engines comprising in combination witha carburetor having a spark advance port, an ignition distributor havingan igniTion spark advance mechanism operated by a spark advance vacuumunit having a vacuum port and a source of direct current potential, avacuum line extending between said carburetor spark advance port andsaid spark advance vacuum unit vacuum port, a two-way valve having anoperating coil included in said vacuum line which is normally in a firstcondition to establish a vacuum connection between said carburetor sparkadvance port and said spark advance vacuum unit vacuum port andoperable, upon the energization of said operating coil, to a secondcondition to vent said vacuum advance unit vacuum port to atmosphere,means for producing a direct current speed signal of a magnitudeproportional to vehicle speed, means for producing a direct currentreference signal of a predetermined substantially constant magnitude,means responsive to said speed signal and said reference signal forproducing a control signal during vehicle acceleration until saidvehicle has accelerated to a speed of a selected magnitude and duringdeceleration after said vehicle has decelerated to a speed less than theselected magnitude, an electrical switching device having normally opencurrent carrying elements operable to an electrical circuit closedcondition in response to said control signal, and means for connectingsaid current carrying elements of said electrical switching device andsaid operating coil of said two-way valve in series across said sourceof direct current potential.
 4. An ignition spark vacuum advance systemfor use with motor vehicle internal combustion engines comprising incombination with a carburetor having a spark advance port, an ignitiondistributor having an ignition spark advance mechanism operated by aspark advance vacuum unit having a vacuum port and a source of directcurrent potential, a vacuum line extending between said carburetor sparkadvance port and said spark advance vacuum unit vacuum port, a two-wayvalve having an operating coil included in said vacuum line which isnormally in a first condition to establish a vacuum connection betweensaid carburetor spark advance port and said spark advance vacuum unitvacuum port and operable, upon the energization of said operating coil,to a second condition to vent said vacuum advance unit vacuum port toatmosphere, means for producing a direct current speed signal of amagnitude proportional to vehicle speed, means for producing a directcurrent reference signal of a predetermined substantially constantmagnitude, means responsive to said speed signal and said referencesignal for producing a control signal during vehicle acceleration untilsaid vehicle has accelerated to a speed of a selected magnitude andduring deceleration after said vehicle has decelerated to a speed lessthan the selected magnitude, an electrical switching device havingnormally open current carrying elements operable to an electricalcircuit closed condition in response to said control signal, means forconnecting said current carrying elements of said electrical switchingdevice and said operating coil of said two-way valve in series acrosssaid source of direct current potential, and means responsive to enginetemperatures less than and greater than a selected engine temperaturerange for diverting said control signal from said electrical switchingdevice.
 5. An ignition spark vacuum advance system for use with motorvehicle internal combustion engines comprising in combination with acarburetor having a spark advance port, an ignition distributor havingan ignition spark advance mechanism operated by a spark advance vacuumunit having a vacuum port and a source of direct current potential, avacuum line extending between said carburetor spark advance port andsaid spark advance vacuum unit vacuum port, a two-way valve having anoperating coil included in said vacuum line which is normally in a firstcondition to establish a vacuum connection between said carburetor sparkadvance port and said spark advance vacuum unit vacuum port andopErable, upon the energization of said operating coil, to a secondcondition to vent said vacuum advance unit vacuum port to atmosphere,means for producing a direct current speed signal of a magnitudeproportional to vehicle speed, means for producing a direct currentreference signal of a predetermined substantially constant magnitude, anoperational amplifier having an inverting input circuit, a non-invertinginput circuit and an output circuit for producing a control signal uponsaid output circuit thereof during vehicle acceleration until saidvehicle has accelerated to a speed of a selected magnitude and duringdeceleration after said vehicle has decelerated to a speed less than theselected magnitude, means for applying said direct current speed signalto said inverting input circuit of said operational amplifier, means forapplying said direct current reference signal to said non-invertinginput circuit of said operational amplifier, and means responsive tosaid control signal for completing an energizing circuit for saidoperating coil of said two-way valve across said source of directcurrent potential.
 6. An ignition spark vacuum advance system for usewith motor vehicle internal combustion engines comprising in combinationwith a carburetor having a spark advance port, an ignition distributorhaving an ignition spark advance mechanism operated by a spark advancevacuum unit having a vacuum port and a source of direct currentpotential, a vacuum line extending between said carburetor spark advanceport and said spark advance vacuum unit vacuum port, a two-way valvehaving an operating coil included in said vacuum line which is normallyin a first condition to establish a vacuum connection between saidcarburetor spark advance port and said spark advance vacuum unit vacuumport and operable, upon the energization of said operating coil, to asecond condition to vent said vacuum advance unit vacuum port toatmoosphere, means for producing a direct current speed signal of amagnitude proportional to vehicle speed, means for producing a directcurrent reference signal of a predetermined substantially constantmagnitude, an operational amplifier having an inverting input circuit, anon-inverting input circuit and an output circuit for producing acontrol signal upon said output circuit thereof during vehicleacceleration until said vehicle has accelerated to a speed of a selectedmagnitude and during deceleration after said vehicle has decelerated toa speed less than the selected magnitude, means for applying said directcurrent speed signal to said inverting input circuit of said operationalamplifier, means for applying said direct current reference signal tosaid non-inverting input circuit of said operational amplifier, meansresponsive to said control signal for completing an energizing circuitfor said operating coil of said two-way valve across said source ofdirect current potential, and means responsive to engine temperaturesless than and greater than a selected engine temperature range forinhibiting said means responsive to said control signal.